Current Bioactive Compounds - Volume 18, Issue 7, 2022

Microbial resistance towards antibiotics has become a global threat to human health. There is currently an urgent need to develop novel antibacterial and antifungal agents with new mechanisms of antimicrobial action and lower levels of toxicity. This paper reviews the structureactivity relationship as well as the antimicrobial effect of substituted rhodanine derivatives. The inhibitory effects of the substituted rhodanines on different, specific antibacterial targets and the potential that rhodanine-derived compounds have to be new antibacterial compounds have been discussed in detail.

Tuberculosis (TB) is a life-threatening infectious disease caused by the bacteria Mycobacterium tuberculosis (MTB), which mostly affects the lungs. According to the World Health Organization (WHO) report 2020, there were over 10 million cases of tuberculosis worldwide, with around 1.4 million people dying, wherein India accounts for over 26% of the global burden. Prolonged treatment, high pill burden, low compliance, development of multiple drug resistance and subsequent intolerable toxicity lead to the emergence of new nanotechnology-based drug delivery approaches involving micro-metric and nano-metric carriers. Nanotechnology is superior to conventional therapies as it offers site specific drug delivery of antimicrobial drugs that increases therapeutic efficacy and reduces systemic toxicity associated with higher doses and also prevents the drug from early degradation, increased solubility and blood retention time. This review focuses on the different nanotechnological carriers via pulmonary route, including liposomes, niosomes, solid lipid nanocarriers, dendrimers, nanoparticles, microspheres and microparticles for tackling the problems related to the treatment of TB. The current review gives a summary of the possible utilization of nanotechnologybased carrier systems to overcome the disadvantages of TB therapy. It also provides a summary of the importance and advancements of directing nanocarriers at bacterial reservoir. Eventually, the article presents an overview of the success in clinical application of such systems.

Background: Herbal plants have been used in medicine for the treatment of numerous human health complications. Plant-derived products, including extract, botanicals, and preparations, have been used in medicine and other allied health sectors since a very early age and have been available in the market for several decades. Flavonoids have been a well-known class of phytochemicals in medicine due to their anti-oxidant, anti-cancer, anti-inflammatory, anti-bacterial and hepatoprotective potential. Methods: In order to know the medicinal importance and therapeutic benefit of cirsimaritin in medicine, in the present investigation, scientific research data have been collected and analyzed from various literature data sources, including Science Direct, Google, Google Scholar, PubMed, and Scopus. Detailed pharmacological activities of cirsimaritin have been analyzed to know the biological potential of cirsimaritin. However, for the standardization of plant material, numerous analytical techniques have been developed in the scientific field, and analytical data of cirsimaritin have been collected and analyzed in the present work. Results: Cirsimaritin, also called 4',5-dihydroxy-6,7-dimethoxyflavone, is a flavonoidal class phytochemical found to be present in the medicinal plant. It has been utilised in medicine to address a wide range of human health issues. Through the analysis of scientific data, it was found that cirsimaritin has numerous health beneficial aspects due to its vast pharmacological activities. Its medicinal importance is mainly due to its anti-oxidant, anti-bacterial, and anti-inflammatory activities. Further data analysis revealed the therapeutic effectiveness of cirsimaritin on breast cancer, gallbladder carcinoma, central nervous system disorders, diabetes mellitus, melanogenesis, immune responses, human erythrocytes, and respiratory burst. The importance of GC-MS, LC-MS, HSSPME, FTIR, ICP-OES, MS, NMR, LC/ESI-MS/MS, HPLC, reversed-phase HPLC, and TLC techniques for the analysis of cirsimaritin has been revealed. Conclusion: The biological importance of cirsimaritin for the treatment of human health complications was revealed; it could also be used for the development of effective medicine against human disorders.

Background: Alzheimer’s disease (AD) is a chronic and prevalent neurodegenerative disease that leads to memory loss, especially in the elderly. AD is caused by a lack of acetylcholine in the brain and oxidative stress. The Cyamopsis tetragonoloba, also known as Guar or cluster bean, is a legume that belongs to the family Fabaceae. It is cheap, widely consumed as a seasoned vegetable, and reported to counteract chronic diseases linked to oxidative stress, such as diabetes, dyslipidemia, inflammation, and ulcer. Objective: The present study was undertaken to assess the anti-alzheimer’s activity of a tender green pod extract of Cyamopsis tetragonoloba on learning and memory impairment induced by scopolamine. Methods: The extract's total phenolic and flavonoid content was determined using a UV-visible spectrophotometer. The Cyamopsis tetragonoloba methanolic pod extract (CTMPE) at a dose of 100 and 200 mg/kg and donepezil 2.5 mg/kg was administered orally for 7 successive days. On the seventh day, a single intraperitoneal injection of scopolamine was used to induce dementia. The behavioral experiments included an elevated plus maze, step-through passive avoidance, radial arm maze, and Y-maze tests were conducted. The mice were sacrificed and acetylcholine, acetylcholinesterase, and oxidative stress markers were measured in brain homogenate. Results: The total phenolic and flavonoid content was found as 12.9 mg of GAE/g and 1.71 mg of QE/g, respectively. Scopolamine caused memory deterioration, as well as changes in acetylcholine, acetylcholinesterase, and increased oxidative stress in the brain. Mice pretreatment with CTMPE at both doses attenuated scopolamine-induced behavioral, neurochemical, and oxidative changes in a similar way to donepezil. Conclusion: The CTMPE showed an anti-amnesic effect that makes it a promising candidate targeting multiple events as a potential strategy to curb the progression of cognitive impairment.

Introduction: This work aimed to create a new platinum-interferon conjugate and investigate its properties. Background: Multiple drug resistance of tumor cells is a serious challenge in modern medicine. Neoplastic diseases are often complicated by persistent bacterial infections, which impairs efficacy and the outcome of anticancer therapy. The development of new bifunctional drugs for the treatment of tumor growth and bacterial complications is an urgent task. Objective: The objective of this study was to evaluate the complex antiblastic and antibacterial properties of interferon-platinum conjugate in vitro. Materials and Methods: The coordination complex of dichloro-N,N,N,N-tetrakis-(2-aminoethyl)- 1,6-hexamethylenediaminobisplatin dichloride was used for production of conjugate with human α-interferon. The binding of a metal complex with protein was established by means of radiochemical neutron activation analysis. As test objects, we used lympholeukemic Jurkat cells line, human lymphocytes in reaction of lymphocyte blastic transformation and different strains of microorganisms, including Staphylococcus aureus and Pseudomonas aeruginosa. Results: Binuclear platinum human α-interferon conjugate has a significant dose-dependent antibacterial and antiproliferative suppressive effect on target cells and bacteria. Conclusion: The tested preparation can be of a certain interest in drug designing for rational antiblastic therapy, especially in the case of infectious complications. This conjugate can be a convenient platform for creating drugs for the complex therapy of oncological diseases with bacterial complications.

Background: Xanthomonas axonopodis pv. citri is a gram-negative bacterium that affects citrus crops, causing a disease known as citrus canker. Although essential oils and other compounds isolated from plants represent a natural alternative to treat this disease, they have the disadvantage of having low solubility in the media in which the bioassays to determine antimicrobial activity are performed. This has led several researchers to evaluate the solubility of plant essential oils in alternative solvents. Objectives: The aim of this study was to evaluate the solubility of the essential oil from Aloysia gratissima as well as that of low-polarity extracts and pure compounds of the genus Flourensia in diluted agar/Tween 80 solutions to test and improve their antimicrobial activity against Xanthomonas axonopodis pv. citri. Methods: Antimicrobial activity against Xanthomonas axonopodis pv. citri was determined by bioautography, agar diffusion, and microdilution methods. Results: The A. gratissima oil showed increased activity in the agar (0.15% m/v)/Tween80 (0.5% v/v) 1:1 mixture, with MIC values ranging from 75 to 100 μL/mL, while Flourensia spp. extracts were more soluble in agar solution (0.15% m/v). The pure compounds tested presented MIC values ranging from 50 to 150 μg/mL. Conclusion: The proven antimicrobial activity of both Aloysia gratissima essential oil and Flourensia spp. extracts and pure compounds allows proposing these natural products as potential antimicrobial agents in the control of citrus canker.

Background: Thymol is a bioactive compound having many pharmacological activities. Objective: The present study was carried out to evaluate the fungi toxic effects of thymol and derivatives against phytopathogenic fungi of maize. Methods: Thymol was derivatized to get formylated thymol, Mannich bases, and imine derivatives. All the synthesized thymol derivatives were characterized by their physical and spectral properties. Synthesized thymol derivatives were screened for their in vitro antifungal effects using poisoned food technique against three maize pathogenic fungi, namely Fusarium moniliforme, Rhizoctonia solani and Dreschlera maydis. Results: Thymol and formylated thymol showed promising results for control of D. maydis with ED50 values less than standard carbendazim and comparable to standard mancozeb. These two compounds were further evaluated for control of D. maydis causative maydis leaf blight disease on maize plants grown in the field during the Kharif season (June to October) 2018. Conclusion: Thymol exhibited significant control of maydis leaf blight disease of maize and emerged as a potential alternative to synthetic fungicides used in cereal crops.

Background: Plants are an abundant natural source of potential chemical compounds; they have been widely used in various industries, such as pharmaceuticals, cosmetics, and food. This work aims to study two Saharan medicinal plants by evaluating the activity of plant extract against bacterial and fungal plant pathogens as well as against the model nematode Caenorhabditis (C.) elegans. Methods: The antimicrobial activity of plant extracts against plants pathogen was assessed in a 96- well plate assay by calculating the percentage of inhibition of bacteria. The antifungal activity against plant pathogenic fungi was evaluated by the agar diffusion method, and inhibition was calculated by measuring the diameter of the inhibition zone. Anthelmintic activity was evaluated by calculating the average movement of C. elegans worms. Preliminary phytochemical screening was realized with HPTLC. Results: Hexane and ethyl acetate extract of Pergularia tomentosa showed broad-spectrum antimicrobial activity. This plant has the potential to act as a broad-spectrum antibacterial biopesticide. Hexane extract of Forsskaolea tenacissima exhibited good activity against one fungus. The extracts of Pergularia tomentosa showed good activity against Caenorhabditis elegans, and the extracts of Forsskaolea tenacissima exhibited a low activity. Preliminary phytochemical screening with HPTLC shows that both plants are rich in steroids and flavonoids. Conclusion: Our study shows that the studied plants may possess a broad-spectrum antibacterial effect with narrow-spectrum antifungal properties which can offer more sustainable crop protection with a much safer environmental and human health impact. Plant extracts that inhibited C. elegans could provide a starting point for the development of new anthelmintic drugs.

Background: The main aim of the study was to compare the neuroprotective potential of Polyherbal Formulation (PHF) with that of an extract of a well-reported anti-parkinson plant, i.e., Mucuna pruriens. Methods: Different PHF combinations (PHFs) were formulated by using hydro-alcoholic extracts and were tested for neuroprotective potential against Mucuna pruriens extract (MPE). In the experimental study, 30 albino mice (Swiss strain, 35-45g) were grouped into Control, MPTP, MPTP+ MPE, MPTP+PHFs, MPTP+ L-DOPA groups. Experimental mice were given PHFs and MPE (50 mg/kg body wt.) by intraperitoneal routes. MPTP (1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine) was given orally for 2 weeks with prior use of PHFs and MPE 20 mg/kg body wt. for 2 weeks. After treatment, a neurobehavioral study was performed as well as neurochemical parameters were evaluated. Results: The results showed that polyherbal formulation improved the performance of the dopaminergic neurons in the substantia nigra region of the brain compared to MPE with respect to MPTP intoxication. A significant reduction was found in spontaneous locomotor activity and rotarod activity in MPTP treated mice in contrast with the control group, in whom these activities were restored by MPTP+MPE and MPTP+PHF1; however, this contrasted with the standard L-Dopa treatment group. This improvement was observed to be significantly better in the MPTP+PHF1 treated group compared to the treatment group of MPTP+MPE. The changes in different parameters occurred after the MPTP treatment. These changes were observed in the levels of malondialdehyde (MDA), conjugated dienes (CD), superoxide dismutase (SOD), and catalase. Conclusion: The study concluded that PHF treatment promotes significant neurogenesis, reduces apoptosis, promotes antioxidant capacity, and restores dopamine levels. PHF contains numerous classes of chemical constituents, which show a synergistic effect for better therapeutic remuneration and neuroprotection compared to the single chemical entity L-DOPA, which is a well-known chemical constituent present in MPE.